The presence of moisture and gases leads to difficulties in many industries and operations. With a slight drop in temperature, condensation can occur in pipelines and reservoirs which can lead to corrosion, scales, freeze-ups, dirt, etc. which may damage instruments and controls and cause blockages in airlines, produce excessive pressure drops, increase downtime and reduce the life of tools. Similarly, in chemical, food and metalworking industries, the presence of moisture in the air and gases produces undesired oxidation. It has also been found that the robotics field requires extremely dry air for the operation of its pneumatic systems.
In order to produce extremely dry air i.e., dew points of −40° Fahrenheit or lower, it is often desirable to use a heat of compression dryer system. In such a system, hot moisture laden air from a compressor is fed through a regenerating tower and then passed to an aftercooler and drain system so that cooled dry air is transferred into and through a drying tower for delivery to an air outlet. In a system such as described, if the compressor is operated at less than capacity, it does not generate enough heat (approximately 250° Fahrenheit) to adequately facilitate regeneration of a tower.
It is desirable to provide an improved twin tower heat of compression drying system that rectifies the drawbacks of the prior system by enhancing the previous dryer design.